The present invention relates to a high voltage resistant edge structure in the edge region of a semiconductor component.
Accordingly, a high voltage resistant edge structure in the edge region of a semiconductor component is provided, which has a semiconductor body, at whose first surface at least one inner zone of a first conductivity type is adjacent, at least one floating guard ring arranged in the inner zone, and at least one inter-ring zone of a second conductivity type arranged between the floating guard rings.
In semiconductor elements, particularly in high voltage resistant power semiconductor components, voltage breakthroughs preferably arise in their edge region outside the doping zones, since the electrical field intensity is especially great there due to the is curvature of the doping zones which is conditioned by the edge. To avoid such voltage breakthroughs, doping zones are arranged in rings about the semiconductor components. These annular doping zones reduce local field intensity peaks in the edge region of the semiconductor component.
Such protective rings are described in the Canadian patent No. 667,423, for example. But since the field intensity must be reduced to almost zero in each of the guard rings, the floating guard rings described there must be dimensioned very wide toward the edge. This edge structure consumes a great deal of space, accordingly.
Furthermore, U.S. Pat. No. 3,405,329 teaches edge structures of semiconductor components with what are known as magnetoresistive rings. These magnetoresistive rings are constructed so as to achieve a largely uniform voltage distribution along the surface of the semiconductor body of a semiconductor component. In this way, field intensity peaks which favor the occurrence of a breakthrough are avoided. The realization of these magnetoresistive rings in the edge region of the semiconductor component is likewise very costly in terms of space.
U.S. Pat. No. 4,468,686 teaches a high voltage resistant edge structure with magnetoresistive rings and annular doping zones arranged under the magnetoresistive rings. These annular doping zones essentially consist of number of cascaded MOS transistors. The design of this edge structure likewise takes up a large amount of space in the edge region of the semiconductor component.